Interpretive Summary: Because carbon dioxide (CO2) is a greenhouse gas, determining how much CO2 is released or consumed by agricultural systems is of interest with regard to global climate change. Although there are a lot of CO2 measurements for many systems, there is very little data for subsistence farms in Africa. In this study, CO2 transport was measured for traditional corn production and corn production using no-till practices in Lesotho, southern Africa. Carbon dioxide concentrations and several weather variables were measured above two small corn fields, one following traditional production practices and the other with no tillage operations. The results indicate that the traditional system evolved more CO2 than the no-till system. This is likely due to the effect that cultivation has on stimulating organic matter decomposition and CO2 production. These results are of interest to researchers and policymakers interested in potential climate change mitigation practices for southern Aftrica.

Technical Abstract:
Soil management practices can either sequester or emit carbon (C). Feeding seven billion people mandates that soils be used intensively for food production, but how these soils are managed greatly impacts soil fluxes of carbon dioxide (CO2). However, the lack of CO2 flux measurements on African subsistence farms makes it difficult to estimate C sequestration rates on subsistence farmer’s fields. This study measured the energy balance and CO2 flux of two contrasting crop management systems in the mountains of Lesotho. The potential of no-till to increase soil C sequestration in Lesotho, Africa, was measured using Bowen ratio energy balance (BREB) data collected over a 1.5 year period, comparing CO2 flux between till and no-till treatments. Two BREB micrometeorological systems were established on 100-m by 100-m sites, both planted to corn (Zea mays) but under either conventional (plow, disk-disk) or no-till soil management systems. This study collected data to add to the knowledge base of the effects of specific agricultural management practices on soil C sequestration in sub-Saharan Africa, using the BREB method to collect CO2 flux and other environmental data over shorter time periods. The BREB system found greater CO2 sequestration over the no-till treatments during the growing and non-growing seasons. The present study verified the applicability of BREB measurement methods to study CO2 sequestration at remote agricultural locations. The results of this study indicate no-till management practices in Lesotho sequester more CO2 than conventional tillage.